The invention relates to a turbine package, and to a method for adapting a turbine package.
A widely used gas turbine, having the designation LM 2500, from General Electric, is produced in two models, the standard version LM 2500 PE (PE) and a new, upgraded model having the designation LM 2500 Plus (Plus).
The Plus version is upgraded from an output of 22 MW for the PE version to 29 MW. The main change made during the upgrading consists in introducing a zero step in the compressor, so that the flow volume through the turbine is increased by 23%. The new step increases the length of the turbine by 13.38" (34 cm). This increase in length results in making the PE and the Plus turbine non-interchangeable, in particular because the bell mouth door of the PE turbine package would collide with the support bracket anchorage points of the Plus turbine if a Plus turbine were placed in a PE turbine package. It is not possible to change the anchorage points of the turbine, since these are carefully determined with respect to the natural frequency of the turbine, thermal influences, the distribution of forces and the flow characteristics at the inlet.
Accordingly, in case of a future upgrading by means of a change from a PE turbine to a Plus turbine, this increased length will involve substantial reconstruction of the turbine package (which comprises turbine, frame and supporting means for the turbine). The reconstruction will be costly and will entail a lengthy standstill before the new turbine can be put into service. Moving the inlet bell mouth door is particularly problematic. The mountings for the turbine on the frame cannot be used either, and it is therefore, in general, just as simple to exchange the whole frame, a process which obviously is very expensive. Moreover, this will make it impossible to change back to a PE turbine later, for example as a reserve turbine when the Plus turbine is undergoing repairs, etc.